I'm trying to figure out the best way to do my water changes for a 90g mbuna tank. I have well water and a water softener that uses salt pellets. My well water is around 25 dgh with a tds of 400 and my softened water is about 0 dgh and has a tds of 500. I'm thinking the most convenient method would be mixing hot softened water with the cold well water when I do water changes. I'm concerned that the sodium in the softened water may be unhealthy for the mbuna. I've been mixing water in a 10g tank with zebra danios and a tetra that I had for over a year and they seem to be doing fine. What do you guys think? Should I continue doing water changes by mixing in softened water that contains 500 tds of sodium?